If you are doing action you will more likely get better results with a lavalier mic (for cheap indie plug this into a Zoom H1 or Tascam DR5 and use the recorder right on the talent. You need to boom shotguns and with action sequences this can be rather a difficult task keeping the mic the optimum 18" from actors mouth. If you are indoors you won't want shotguns either. Mics are always a decision of the environment and there is no single one that works well all around.

Don't forget your smartphone. A decent lav can go into a smartphone which can go into your actor's pocket.

The only issue with a lav mic is you need one for each actor. With a shotgun, you need only one mic, but someone has to hold and point it.

The problem is this is a question where the OP is hoping for a single "best" answer, and there isn't one. There is no single mic or recording method that is "best." It always depends on what's being shot.

IMO a shotgun mic would be nice, but not something that you would need for a very long time. It also require a boom operator, Im guessing youll be the DP?

A lav or two for shooting and a USB condenser mic would be the way to go in my opinion. My USB mic is using a cardiod pattern, so it doesnt even pick up my blue switch mechanical keyboard. And when the range isnt limited, it makes a fantastic mic for VOs or ADR, even foley should you be into that.

"Decent" Shotgun mics are going to be 200 USD at least. Decent lavs can be had for 40 USD. So for an action sequence you can cover 3 actors for a little more than half the cost of a "decent" shotgun assuming you have a smartphone for each. A shotgun is useful for recording outdoor dialogue when boomed properly at less than 2 feet from the actors mouth. That is a very narrow use. Recording audio is critical for filming and it is ALL about mic placement. Indie filmmakers hear "get a shotgun" which is bad advice IMO. If most of your filming is indoor dialogue you want a cardiod mic. Where there is a lot of motion with a wide scene a Lav is better.

Bottom line: There is a reason there are so many mic types. One will not cover it all. Pic a mic that is applicable to what you are shooting. If you are on a budget consider Ebay for your needs (however the good mics are not that much discounted for used.)

Audio quality is very good in the low end, and you mask poor audio quality (compared to expensive mics) with music, etc. When you do voice overs thats when for example you want a dead room and a high end mic. That'¨s how I look at it, no reason to fall for "marketing scams" as I call them. Honestly, I would watch real budget YouTube videos on this topic and not where they're sponsored by big and high end audio companies, that might help OP a lot, who knows.

@RaghavBhat Audio is almost as involved as video. Think of recorders as cameras and mics as lenses and you'll get a sense of what I mean.

And that's before you get into nuttiness like mid-side stereo mics that can record clean dialog at 1/4 of a mile. Those are very annoying outdoors, sometimes, though having the mid-side control in post is also rather nice. Some sound designers' heads explode when they see that, others revel in the freedom...

If you want a good shotgun mic then your not going to get when for under $50. As a beginners mic for $200 you can get the Sennheiser Mke 400. It provides pretty decent audio and very good for it's price.